Modules constructed from refractory fiber blankets are used in insulating the inner walls of high temperature furnaces. Exemplary of such modules are U.S. Pat. Nos. 3,952,470; 4,001,996; and 4,055,926. Repeated exposure to high temperatures can cause the fibers in some of the modules to shrink. This may result in some looseness between adjacent modules which would permit heat loss directly to and through the walls of the furnace.
One suggested remedial measure is described in U.S. Pat. No. 4,194,282. In that patent, a length of blanket which is equal to or exceeds the length of one complete modular fold, is wedged between such adjacent modules with the help of two spacer plates and a pusher blade. The heat loss through these gaps which were created by shrinkage is effectively halted. However, the ends of the filler blanket are positioned along the hot face of the furnace. The ends of the fibers in the blanket ends are thereby exposed to the highest temperatures and these fiber ends are most susceptible to heat induced shrinkage. In addition, these blanket ends make for a non-uniform, unsightly appearance.
The mini-module of the present invention solves these problems. A length of refractory fiber blanket is twice folded to position the ends toward each other preferably forming a butt joint. The mini-module is then wedged between two modules in the same manner as was done previously. The butt joint will be positioned on the side of the mini-module at some point located between the hot face and the cold face of the adjacent modules, protecting the fiber ends from the extreme temperatures inside the furnace. In order to effect the greatest amount of protection, it is preferred that the butt joint be located closer to the cold face than to the hot face so that the temperature to which the end fibers are exposed is no greater than necessary.
Other features, advantages and characteristics of the present invention will become apparent after a reading of the following specification.